Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2014

Severe Thunderstorm Warning 9, NWS Philadelphia/Mount Holly

April 22, 20144 states

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Apr 22, 2014, 7:21 PM EDT for 4 states. It was in force for 39 min. 3 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Apr 22, 2014, 7:21 PM EDT (23:21 UTC)
Expired: Apr 22, 2014, 8:00 PM EDT
In force: 39 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

Counties New Castle County, DE, Cecil County, MD, Gloucester County, NJ, Salem County, NJ, Berks County, PA, Chester County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 98 km from the middle of the area, began a volume at 23:21 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What was reported inside it

Time	Report	Where	Remark
Apr 22, 7:34 PM EDT	HAIL 0.75	West Chester, PA
Apr 22, 7:53 PM EDT	TSTM WND DMG	Philadelphia, PA	TREES DOWN IN WEST PHILADELPHIA
Apr 22, 7:55 PM EDT	TSTM WND DMG	Roxborough, PA	TREES DOWN IN ROXBOROUGH PART OF PHILADELPHIA

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 11.4 hours before the alert went out and 64 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1670 m above ground
0-6 km bulk shear: 40 kt
0-1 km storm-relative helicity: 120 m²/s²
0-3 km storm-relative helicity: 151 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

176 
WUUS51 KPHI 222321
SVRPHI
DEC003-MDC015-NJC015-033-PAC011-029-045-091-101-230000-
/O.NEW.KPHI.SV.W.0009.140422T2321Z-140423T0000Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
721 PM EDT TUE APR 22 2014

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHEASTERN BERKS COUNTY IN EASTERN PENNSYLVANIA...
  MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...
  WESTERN PHILADELPHIA COUNTY IN SOUTHEAST PENNSYLVANIA...
  DELAWARE COUNTY IN SOUTHEAST PENNSYLVANIA...
  NORTHWESTERN GLOUCESTER COUNTY IN SOUTHERN NEW JERSEY...
  NORTHERN NEW CASTLE COUNTY IN NORTHERN DELAWARE...
  NORTHEASTERN CECIL COUNTY IN NORTHEAST MARYLAND...
  CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...
  NORTHWESTERN SALEM COUNTY IN SOUTHERN NEW JERSEY...

* UNTIL 800 PM EDT

* AT 718 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  LINE OF SEVERE THUNDERSTORMS. ..MOVING EAST AT 40 MPH. THESE STORMS
  ARE CAPABLE OF PRODUCING ONE INCH DIAMETER HAIL...AND DAMAGING
  WINDS IN EXCESS OF 60 MPH. 

* SEVERE THUNDERSTORMS WILL AFFECT THE FOLLOWING LOCATIONS AMONG 
OTHERS...ROYERSFORD...PHOENIXVILLE... EXTON...MARSHALLTON...KING OF 
PRUSSIA...RADNOR...AMBLER...NORRISTOWN...HOCKESSIN...PAULSBURG.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS LINE OF SEVERE THUNDERSTORMS HAS A HISTORY OF PRODUCING WIND 
DAMAGE.

THIS SEVERE THUNDERSTORM MAY CONTAIN LITTLE OR NO LIGHTNING. DO NOT 
WAIT TO HEAR THUNDER BEFORE TAKING COVER. 

&&

LAT...LON 3997 7579 4037 7575 4024 7519 4023 7517
      3982 7513 3962 7557 3962 7558 3968 7552
      3969 7553 3966 7554 3963 7560 3974 7610
TIME...MOT...LOC 2319Z 288DEG 36KT 4027 7568 3994 7565
          3974 7604

$$

ROBERTSON

1 follow-up statement

729 
WWUS51 KPHI 222339
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
739 PM EDT TUE APR 22 2014

MDC015-PAC011-222347-
/O.CAN.KPHI.SV.W.0009.000000T0000Z-140423T0000Z/
BERKS PA-CECIL MD-
739 PM EDT TUE APR 22 2014

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN CECIL AND
SOUTHEASTERN BERKS COUNTIES IS CANCELLED...

THE STORM THAT PROMPTED THE SEVERE THUNDERSTORM WARNING HAS MOVED OUT
OF THE AREA...THEREFORE THE SEVERE THUNDERSTORM WARNING HAS BEEN
CANCELLED.

LAT...LON 3993 7564 4026 7566 4024 7519 4018 7516
      3982 7513 3962 7557 3968 7552 3969 7553
      3966 7554 3963 7560 3968 7575 3969 7576
TIME...MOT...LOC 2337Z 288DEG 36KT 4020 7545 3987 7543
          3968 7582

$$

DEC003-NJC015-033-PAC029-045-091-101-230000-
/O.CON.KPHI.SV.W.0009.000000T0000Z-140423T0000Z/
MONTGOMERY PA-PHILADELPHIA PA-DELAWARE PA-GLOUCESTER NJ-NEW CASTLE 
DE-CHESTER PA-SALEM NJ-
739 PM EDT TUE APR 22 2014

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 800 PM EDT
FOR NORTHWESTERN SALEM...EASTERN CHESTER...NORTHERN NEW CASTLE...
NORTHWESTERN GLOUCESTER...DELAWARE...WESTERN PHILADELPHIA AND
SOUTHERN MONTGOMERY COUNTIES...

AT 734 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING ONE INCH
DIAMETER HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH. ALONG A LINE
EXTENDING FROM WEST CENTRAL MONTGOMERY COUNTY TO CENTRAL DELAWARE
COUNTY TO NORTH CENTRAL CECIL COUNTY...MOVING EAST AT 40 MPH.

* SEVERE THUNDERSTORMS WILL AFFECT THE FOLLOWING LOCATIONS AMONG 
OTHERS...ROYERSFORD...VALLEY FORGE...PAOLI...PHOENIXVILLE...WEST 
CONSHOHOCKEN...MARSHALLTON...KING OF PRUSSIA...RADNOR... 
AMBLER...NORRISTOWN...PHILADELPHIA...PAULSBORO.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS LINE OF SEVERE THUNDERSTORMS HAS A HISTORY OF PRODUCING WIND 
DAMAGE.

LAT...LON 3993 7564 4026 7566 4024 7519 4018 7516
      3982 7513 3962 7557 3968 7552 3969 7553
      3966 7554 3963 7560 3968 7575 3969 7576
TIME...MOT...LOC 2337Z 288DEG 36KT 4020 7545 3987 7543
          3968 7582

$$

ROBERTSON

The office that day

Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 22, 3:23 PM EDT	Fire Weather Watch	PHI	Berks, Bucks, Carbon, Chester, Delaware, Lehigh and 4 more	13 hr
Apr 22, 5:55 PM EDT	Special Weather Statement	PHI	Berks, Lehigh	65 min
Apr 22, 6:41 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Chester, Montgomery	49 min
Apr 22, 6:54 PM EDT	Special Weather Statement	PHI	Berks, Lehigh, Northampton	51 min
Apr 22, 7:52 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Delaware, Montgomery, Philadelphia	38 min
Apr 22, 3:34 AM EDT	Gale Watch	PHI		12 hr
Apr 22, 3:34 AM EDT	Small Craft Advisory	PHI		30 hr
Apr 22, 3:38 PM EDT	Gale Warning	PHI		44 hr
Apr 22, 7:45 PM EDT	Special Weather Statement	PHI	Cumberland, Gloucester, Salem	60 min
Apr 22, 7:10 PM EDT	Special Weather Statement	PHI	Cecil	50 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2014 Severe Thunderstorm Warnings in New Jersey, 2014 Severe Thunderstorm Warnings in Delaware, 2014 Every severe thunderstorm warning in 2014

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.